People around plat and diamond can assume when she ' ll have her ult and focus her . She doesn ' t have enough self peel and survivability without her teammates to reliably stay alive if your team is tunnelling during a fight but their flanker is on you . The second or two it takes to make the call out may be enough for a decent player to kill you . And more often than not you ' ll just res people into a meat grinder . It takes more communication than you ' d think to make everyone suicide on the point without using any ultimates so you can fly in and revive them . But even if they did , you could die flying in to res them if their McCree or roadhog are on point . There ' s just a lot of variables that need to be in a good condition to be a really effective mercy , and the higher you go , the lower chances these variables have of being present .