diff --git a/bench/run b/bench/run
index 8e7cb5b..944dc2c 100755
--- a/bench/run
+++ b/bench/run
@@ -24,7 +24,7 @@ for r in *; do
   echo "Running $r..."
   pushd "$r" >/dev/null
   out="$results_dir/$r.json"
-  sudo --preserve-env=MHB_HTML_ONLY,PATH MHB_ITERATIONS="$iterations" MHB_INPUT_DIR="$input_dir" nice -n -20 taskset -c 1 ./run >"$out"
+  sudo --preserve-env=MHB_HTML_ONLY,PATH MHB_ITERATIONS="$iterations" MHB_INPUT_DIR="$input_dir" RUST_BACKTRACE=1 nice -n -20 taskset -c 1 ./run >"$out"
   popd >/dev/null
 done
 popd >/dev/null
diff --git a/bench/runners/minify-html-onepass/src/main.rs b/bench/runners/minify-html-onepass/src/main.rs
index 5606ad1..5351f34 100644
--- a/bench/runners/minify-html-onepass/src/main.rs
+++ b/bench/runners/minify-html-onepass/src/main.rs
@@ -7,7 +7,7 @@ use minify_html_onepass::{Cfg, in_place};
 fn main() {
     let iterations = env::var("MHB_ITERATIONS").unwrap().parse::<usize>().unwrap();
     let input_dir = env::var("MHB_INPUT_DIR").unwrap();
-    let html_only = env::var("MHB_HTML_ONLY").unwrap() == "1";
+    let html_only = env::var("MHB_HTML_ONLY").ok().filter(|v| v == "1").is_some();
 
     let tests = fs::read_dir(input_dir).unwrap().map(|d| d.unwrap());
 
diff --git a/bench/runners/minify-html/src/main.rs b/bench/runners/minify-html/src/main.rs
index ae1e67f..8488791 100644
--- a/bench/runners/minify-html/src/main.rs
+++ b/bench/runners/minify-html/src/main.rs
@@ -7,7 +7,7 @@ use minify_html::{Cfg, minify};
 fn main() {
     let iterations = env::var("MHB_ITERATIONS").unwrap().parse::<usize>().unwrap();
     let input_dir = env::var("MHB_INPUT_DIR").unwrap();
-    let html_only = env::var("MHB_HTML_ONLY").unwrap() == "1";
+    let html_only = env::var("MHB_HTML_ONLY").ok().filter(|v| v == "1").is_some();
 
     let tests = fs::read_dir(input_dir).unwrap().map(|d| d.unwrap());