There are two alternative ways to correct this grammatical error:
We watched with incredulity as (Correction Method 1: delete "as") former-president-turned-convicted-felon Donald Trump survive (Correction Method 2: Leave "as" in but change survive and secure to the simple past - survived and secured) an assassination attempt and secure the Republican presidential nomination.
There are two alternative ways to correct this grammatical error:
We watched with incredulity as (Correction Method 1: delete "as") former-president-turned-convicted-felon Donald Trump survive (Correction Method 2: Leave "as" in but change survive and secure to the simple past - survived and secured) an assassination attempt and secure the Republican presidential nomination.