In fact here are the holds for the top 12 the weekend after the shooting:
2 2 Ice Age: Continental Drift Fox $13,352,646 -34.6% 3,869 -17 $3,451 $114,899,860 $95 3 3 N The Watch Fox $12,750,297 - 3,168 - $4,025 $12,750,297 $68 1 4 N Step Up Revolution Sum. $11,731,708 - 2,567 - $4,570 $11,731,708 $33 1 5 4 Ted Uni. $7,353,150 -26.6% 3,129 -85 $2,350 $193,618,750 $50 5 6 3 The Amazing Spider-Man Sony $6,701,111 -38.4% 3,160 -593 $2,121 $241,953,721 $230 4 7 5 Brave BV $4,305,153 -28.5% 2,551 -348 $1,688 $217,329,672 $185 6 8 6 Magic Mike WB $2,619,128 -39.0% 2,075 -531 $1,262 $107,625,983 $7 5 9 7 Savages (2012) Uni. $1,838,215 -45.9% 1,414 -922 $1,300 $43,983,785 $45 4 10 9 Moonrise Kingdom Focus $1,434,904 -21.7% 853 -42 $1,682 $38,641,403 $16 10 11 8 Tyler Perry's Madea's Witness Protection LGF $1,308,870 -41.9% 1,111 -429 $1,178 $62,736,167 $20 5 12 10 To Rome with Love SPC $1,000,279 -29.6%
Almost everything dropped sub 40%, several even sub 30%. But yes, CLEARLY there was still such a huge impact.