What do lines 7-9 of Canto 23 of Dante's Inferno mean?

In Canto 23, Dante worries that the demons will come after him and his companion, Virgil. While he ponders their fate, he is reminded of the soul of Navarre in the previous Canto and all that the unfortunate soul suffers at the hands of the demons. This is why he tells us that the 'present fray' has turned his thoughts towards the parable of the mouse and the frog. He is uncomfortably cognizant of the fact that there are parallels between the soul of Navarre's fate in Canto 22 and the fate of the mouse and frog in the parable. Dante clearly sees the soul from Navarre as the hapless mouse who is subjected to the mercies of the frog (the demons).

Comparing the two situations worries him to the point that he pleads with Virgil the necessity of hiding from the demons. Before we continue, I will briefly explain the parable of the frog and mouse. In the story (attributed to Aesop), a mouse wants to cross a pond. Without options, he reluctantly agrees to ride on the back of a frog. The frog, however, isn't really the kind soul he presents himself to be. He actually plans to drown the mouse when the two approach the middle of the pond. In the meantime, the sly frog suggests that the mouse tie himself to his back to prevent himself from falling off during the crossing. The mouse does so, but to his regret, soon discovers  the frog's true intentions. So, the mouse struggles to free himself; unluckily for him, however, an eagle catches sight of the mouse and swoops down to retrieve the mouse for his dinner. Since the frog and the mouse are tied together, the eagle ends up eating both animals for his supper.

In Canto 22, the soul of Navarre manages to flee from the demons by plunging into the depths of the boiling pitch. Supposedly on a mission to call up seven Italians from the boiling depths, the soul of Navarre manages to cause at least two demons to be plunged into the burning pitch with him. Now, this is where some experts disagree on which party represents the frog and which represents the mouse. Some argue that the soul of Navarre is the mouse and the demons, the frog: as the sly frog eventually shares the terrible fate of the mouse, so do the demons (the frog) suffer the same fiery punishment as the soul of Navarre (the mouse).

Other experts argue that the soul of Navarre IS the frog and the demons, the mouse. This is because they assert that the soul of Navarre (frog) tricks the demons (mouse) into jumping in after him and getting stuck in the boiling pitch. However, I see some difficulties with this interpretation, as the mouse is never presented in the parable as one who desires harm to come to the frog. Just the opposite is true with the frog: he means for the mouse to drown. Similarly, in Canto 22, the demons mean to inflict physical tortures on any soul they catch trying to escape the boiling pitch. To then equate them with the mouse figure becomes problematic.

To get back to our discussion, lines 6-9 demonstrate Dante's growing realization that the demons cannot be trusted and that any entanglement with them will inevitably lead to terrible suffering. This is why he is so fearful and why he strongly impresses on Virgil the necessity of hiding.