Theories

Warning This Section Does Contain Spoilers

What if Sven stabbed Penny for a specific reason and what if that reason was to help her. What if he knew that would generate an incident report that would have the "Priority Code" that we needed on it. In order to get us this code he had to stab her so she would receive a copy of her report. He probably knows her affinity for sending us paperwork and figured she would send us a copy of this as well. This might be the reason for the sudden change of heart and for him giving her the friendship bracelet and trying to apologise so quickly.