Muties don't attack Ola in the sewers.

[nosaM]

I was able to lure them both together but they did not attack each other.

[PhrygianDominant]

It may not be the best solution, but since Ola is a critical NPC we intentionally made him so that he's not hostile to the muties, as his death would pretty much break the main story. Nowadays we let everyone die and handle the questlines accordingly, but that quest was designed in... ancient times.