Create a new column depending on different values in other columns R

I have a big data set that in its short version looks like this:

> df
Stimulus    TimeDiff
S102        10332.4
S 66        1095.4
S103        2987.8
S 77        551.4
S112        3015.2
S 66        566.6
S114        5999.8
S 88        403.8
S104        4679.4
S 88        655.2

I want to create a new column df$Accuracy where I need to assign correct, incorrect responses, and misses depending on certain values (only S 88, S 66, S 77) in the df$Stimulus and in df$TimeDiff. For example, if S 88 is preceded by S114 or S104 and df$TimeDiff for that row is less than 710 then assign "incorrect" in df$Accuracy. So the data set would look like this:

> df
Stimulus    TimeDiff     Accuracy
S102        10332.4      NA 
S 66        1095.4       NA
S103        2987.8       NA
S 77        551.4        NA
S112        3015.2       NA
S 66        566.6        NA
S114        5999.8       NA
S 88        403.8        incorrect
S104        4679.4       NA
S 88        655.2        incorrect 

What is the best way to do it?