I know that my reply is not likely the answer you're looking for, but still, I thought it could be useful for someone.
I immediately thought of 'the hero story' vs. 'the villain story', and in your case, the character that you call MC could easily be the person that everyone else sees as the villain - Hear me out;
If he does try to solve the issue himself (maybe he already failed at getting help from more powerful people), he might do it to save not only himself but also his family and friends - they are probably infected too. To most people, this will be an understandable reason for doing something, but the reader might not learn this reason at first.
If, then, you have another character, who doesn't know the original MC, who lives on this planet. This other character could have connections to the scientist/scientists who could help solve the issue. What this/these character(s) will then experience is a random person coming to their planet, infecting civilians while demanding the attention of acclaimed scientists, perhaps with trouble describing why.
When this happens, your other character might witness this or hear about it, and learn that the scientists refuse to meet a stranger's demands, after which the 'MC' feels forced to kidnap the scientists or hold them hostage in the building of their sciences.
Perhaps your other character is then captured in the same building and feels the need to 'save' their coworkers (the scientists), and that is how the story "begins"...
That other character could very well be the first to realize that 'the MC' is not actually a villain. After all, very few villains see themselves as a bad guy.
Just an idea.