Of the other two options, Gordon was really attracted to the [Lichen Beast] form. This was exactly what he needed in the present moment. If Portensa could evolve into something that could help him survive his current situation then he could be that much more confident. Living through the next 24 days was his primary concern.
The [Lichen Beast] evolution description didn't give him much information, but he thought he could reasonably estimate that his chances of success would double. For example if he had a 0.01% chance of finding and destroying the apocalypse system currently targeting him then maybe he would have a 0.02% change of living through this.
As low as he estimated his chances, not matter how small the doubling was, it was still double the likelihood. This could not be dismissed.
