Mayumi has to realize being a burden is only bad if its forever. Seki once said he won't care for Tatsuhiko until he climbs out of the trash and gives back to Burst. But he eventually did. We all start out as a burden, what's important is finding our footing and paying back our metaphorical and literal debts!
Ushio is a jerk when it comes to people below him or people outside of Burst!! Wow.. And Soga wasn't phased by it at all.